/*******************************************************************************************
 * Copyright (c) 2006-2009 Alex Robson, Rob Simmons, Craig Israel, and Rachel Twyford
 *
 * Use of this software in any form requires that you have both 
 * read and agreed to the following terms:
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation 
 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions: 
 *
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice, 
 * this list of conditions and the following disclaimer in the 
 * documentation and/or other materials provided with the distribution.
 * Neither the name of Nvigorate nor the names of its contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * ****************************************************************************************/

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
using Nvigorate.Common;
using PostSharp.Extensibility;
using PostSharp.Laos;
using System.Linq;
using Nvigorate.Extensions;

namespace Nvigorate.Aspect
{
    /// <summary>
    /// Apply this attribute to a class to automatically apply a null argument checking aspect to
    /// every function in the class. The aspect will throw an ArgumentNullException if any argument 
    /// is provided to any function in the class specifying the class, method name and argument which 
    /// the null was provided for.
    /// </summary>
    [MulticastAttributeUsage(MulticastTargets.Class | MulticastTargets.Method)]
    public class ArgumentCheckAspect : CompoundAspect
    {
        public override void ProvideAspects(object element, LaosReflectionAspectCollection collection)
        {
            if (element is MethodInfo)
            {
                var method = element as MethodInfo;
                AddAspectToMethod(method.DeclaringType, method, collection);
            }
            else
            {
                Type targetType = element as Type;
                targetType
                    .GetMethods(BindingFlags.Public | BindingFlags.NonPublic)
                    .ToList()
                    .ForEach(method => AddAspectToMethod(targetType, method, collection));
            }
        }

        private void AddAspectToMethod(Type targetType, MethodInfo method, LaosReflectionAspectCollection collection)
        {
            NullArgCheck advice = new NullArgCheck();
            if(!method.Name.Contains("get_") 
               && !method.Name.Contains("set_") 
               && !method.DeclaringType.Equals(typeof(object)))
            {
                //This will output a line to the console during build so that join points can be easily identified
                Console.WriteLine("Applying Null Argument Check aspect to method {0} on type {1}", method.Name, targetType.FullName);
                collection.AddAspect(method, advice);
            }
        }

        [Serializable]
        public class NullArgCheck : OnMethodBoundaryAspect
        {
            public override void OnEntry(MethodExecutionEventArgs eventArgs)
            {
                var values = eventArgs.GetReadOnlyArgumentArray();
                if(values != null && values.Length > 0 && values.Contains(null))
                {
                    var parameters = eventArgs.Method.GetParameters();
                    var parameterValues = parameters.ZipToDictionary(values);
                    var nullParameters = parameterValues.Where(p => p.Value == null);
                    if(nullParameters.Count() > 0)
                    {
                        var targetType = eventArgs.Instance == null ? eventArgs.Method.ReflectedType : eventArgs.Instance.GetType();
                        var violators = DelimitedBuilder.Construct(nullParameters.Select(p => p.Key.Name), ",");
                        throw new ArgumentNullException(string.Format("Parameter(s) {0} cannot be null for method {1}.{2}",
                                                                      violators,
                                                                      targetType.FullName,
                                                                      eventArgs.Method.Name));
                    }
                }
                base.OnEntry(eventArgs);
            }
        }
    }
}
